service_call_examples.rb

class CreateUserService
  def initialize(user_attributes)
    @user_attributes = user_attributes
  end

  def call
    puts "Creating user with following attributes.."
    p @user_attributes
  end
end

user_attributes = {
  email:    'pg@gmail.com',
  password: 'secret'
}

CreateUserService.new(user_attributes).call

# OUTPUT in terminal
# Creating user with following attributes..
# {:email=>"pg@gmail.com", :password=>"secret"}

adhoc_proc = ->(u_attributes) do
  puts "Creating user with following attributes.."
  p u_attributes
end

# p adhoc_proc.class # => Proc

adhoc_proc.call(user_attributes)

# OUTPUT in terminal, exact same!
# Creating user with following attributes..
# {:email=>"pg@gmail.com", :password=>"secret"}


# Another way of building your service would give you
# the exact same signature as a proc/lambda
class CreateUserServiceWithAttributesGivenToCallMethod
  def call(user_attributes)
    puts "Creating user with following attributes.."
    p user_attributes
  end
end

CreateUserServiceWithAttributesGivenToCallMethod.new.call(user_attributes)

# Yet another way of building your service, still respecting the #call method proc interface
class CreateUserServiceWithAttributesGivenToCallMethod
  def self.call(user_attributes)
    puts "Creating user with following attributes.."
    p user_attributes
  end
end

CreateUserServiceWithAttributesGivenToCallMethod.call(user_attributes)


# Going full circle to Pierre Gabriel examples, yet another way
# of *calling* your service 😁
class CreateUserServiceWithAttributesGivenToCallMethod
  def self.call(user_attributes)
    puts "Creating user with following attributes.."
    p user_attributes
  end
end

CreateUserServiceWithAttributesGivenToCallMethod.(user_attributes)

This is what you get in terminal running the whole file at once